State Manager for Stateful Signature Scheme Security
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Solution Overview
Problem
State reuse in stateful signature schemes compromises security, as signers may inadvertently use previously used states to generate signatures, leading to loss of security and integrity in authentication processes.
Innovation Solution
A state manager is introduced to control the release of signatures, determining whether the state used to derive the signature is free or not, ensuring that only signatures from unused states are verified and released, thereby preventing state reuse and maintaining the security of the stateful signature scheme.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a signer speculatively produces a signature using an OTS private key derived from a state selected by the signer, then the signer can operate without knowing whether the state has already been used, but the risk of state reuse increases, compromising security
Solution Approach 1:
A state manager is introduced as an intermediary between the signer and the verification system. The state manager receives signatures from signers, determines whether the used state is free (unused), and controls the release of signatures to verifiers. This intermediary resolves the contradiction by allowing signers to operate freely while maintaining security through centralized state tracking and control.
2Reliability
If the state manager controls whether to release the signature based on knowledge of whether the state is free, then security is maintained, but the system complexity increases
Solution Approach 1:
The state manager performs multiple functions: receiving signatures from signers, determining whether used states are free, controlling signature release to verifiers, and updating the record of used states. By consolidating these diverse functions into a single multi-functional component, the system achieves security without proportionally increasing complexity.
3Reliability
If signatures are encrypted to the state manager and only decrypted if the state is free, then state reuse is prevented, but the verification process becomes more complex
Solution Approach 1:
The state manager performs preliminary determination of whether a state is free before allowing signature decryption and release. By checking the state status in advance and only decrypting signatures from free states, the system prevents state reuse while maintaining a relatively simple verification process for legitimate signatures.
4Reliability
If multiple signers use the same private seed value to generate OTS private keys, then resiliency is introduced, but the coordination of state management becomes more difficult
Solution Approach 1:
The state manager serves as a central intermediary that coordinates state management for multiple signers. Each signer uses the same private seed value to generate OTS private keys, but the state manager tracks which states have been used by any signer and controls signature release accordingly. This intermediary approach enables resiliency through seed sharing while simplifying state coordination through centralized management.
Data Source
AI summary
In an example, a computing device is described. The computing device comprises a communication interface and a processor. The processor is to determine whether a signature, produced by a signer, is derived from a free state under a stateful signature scheme. The free state is a state that has not been used as an input to generate a signing key. The signature is encrypted by the signer. The processor is further to, in response to determining that the signature is derived from a free state, decrypt the encrypted signature. The processor is further to transmit the decrypted signature to a recipient via the communication interface.